Fix logout 405 error by using POST form

Update README.md

chore: update dependencies to latest versions

Update README with system overview and features

Fix line too long

Impliment logic to export purchases to an Excel file using Django and Openpyxl

Ensure that the quantity of an Item is increased when a Purchase is made

Ensure the quantity of an Item is reduced when a sale is made

Update README.md

Update README.md

Fix styling

Fix chart not displaying

organize css

include pagination

improve design